This invention relates to an interfacial process for the production of high molecular weight polycarbonates wherein high molecular weight prepolymers are first formed using one or more motionless mixers and are then coupled to form the polycarbonates.
It is known from U.S. Pat. No. 3,674,740 that polycarbonates can be made from carbonate forming monomers in a tubular reactor using a series of mixing tubes and residence time tubes. However, this known process is designed to produce emulsions which are difficult to process for the recovery of the polycarbonate resins. Other related processes for the production of polycarbonates are known from U.S. Pat. Nos. 3,974,126 and 3,530,094, but none of these patents teaches the making of high molecular weight prepolymers and the polymerization thereof.
A continuous process for making linear polycarbonate is disclosed in U.S. Pat. No. 4,847,352. However, this patent does not disclose use of that process for making branched polycarbonate.